This invention relates generally to undercarriages for adverse terrain vehicles, and more particularly to a detachable undercarriage having either three or four tired wheels which may be utilized to support and propel virtually any type of mechanism.
Traditionally, adverse terrain vehicles have been track types vehicles. For example, track type buildozers, loaders, cranes, and similar devices have been known for decades. In some instances track type mechanisms of this type have utilized undercarriages to support and propel the mechanism. Such an undercarriage may comprise a frame for attachment to the mechanism, structure mounted on the frame for guiding a track around a predetermined course, and a drive motor for actuating the track around the course and thereby propelling the mechanism supported by the undercarriage.
More recently, adverse terrain vehicles utilizing tired wheels have been developed. For example, see U.S. Pat. No. 3,799,362 granted to Applicants herein on Mar. 26, 1974. However, there has not heretofore been provided an undercarriage whereby a tired type vehicular supporting and propelling apparatus adapted for adverse terrain usage could be adapted to virtually any type of mechanism. It has also been found to be desirable to provide a tired type adverse terrain undercarriage having greater load carrying capacity than has been available heretofore.
The present invention comprises a detachable undercarriage for adverse terrain vehicles which overcomes the foregoing and other problems long since associated with the prior art. In accordance with the broader aspects of the invention, an undercarriage includes an elongate hollow frame having a plurality of axle members rotatably supported thereon. Each axle member extends to a wheel support member. Solid or pneumatic tired wheels can be utilized. Preferably all the wheel support members are positioned on the same side of the frame. A drive assembly includes a motor and a transmission mounted on the frame with a dual drive sprocket and separate chains connecting the output of the transmission to one of the endmost axle members and to a middle axle member driven by the transmission to the other endmost axle. The motor can be of either the hydraulic or electric variety.
Either three of four nonaligned axle members carrying wheels of equal diameters can be utilized. In the case of three axle members the center axle member and in the case of four axle members the center two axle members rotate about axes situated below a plane extending through the axes of rotation of the endmost two axle members. This facilitates the skid steering of a mechanism supported and propelled by the undercarriage, while simultaneously making wheels carried by all of the axle members available for ground contact under adverse terrain conditions. If desired, structure may be provided for bringing all of the axle members into alignment in order to provide increased stability.
Either three or four aligned axle members carrying wheels of unequal diameters can be utilized. The center axle in the case of three axle members and the center pair of axles in the case of four axle members carry wheels relatively larger than those carried by the endmost axle members. The same result is accomplished, namely the facilitation of skid steering of the mechanism supported and propelled by the undercarriage with the concurrent availability for ground contact under adverse terrain conditions of all the wheels.
In accordance with still other aspects of the invention, the frame is a hollow load-bearing structure comprised of structural members around its entire periphery and throughout its entire length. This facilitates attachment of a mechanism to the undercarriage at any point along the entire length and around the entire periphery of the frame. The positioning of the hydraulic or electric motor relative to the frame can be varied in order to vary the spacing between the axle members. The motor is preferably drivingly connected to one of the axle members by means of a first drive sprocket connected to the output of the motor, a second drive sprocket connected to one of the axle members, and a drive chain interconnecting the two drive sprockets.